Glock slide-lock issue

[reidnez]

Hey guys, I just picked up a new G19 the other day and went to the range yesterday. I fired off 200 rounds from one of the factory 10-round magazines, didn't try the other one.

Anyway, about 4 times the slide failed to lock back after the last round--it went forward on an empty chamber. The rest of the time it locked back as it should.

I'm strongly suspecting the magazine, but of course it could be something in the pistol. Should I contact Glock and try to get a new magazine? It's tough to troubleshoot because, as I said, it only happened 4 times in 200 rounds. And for about half of the session I was only loading 5 rounds at a time, so I'd estimate there were 4 malfunctions in about 30 magazine changes. Next time I go to the range I'll shoot the other magazine and see what happens. Something else I just thought of is that maybe I'm inadvertently holding down the slide lock. I've never done it with other pistols, but I don't have much experience with Glocks and their very small lever...so operator error is a possibility.

It's not a huge issue, but it's a new pistol and if I can get it fixed I want to. Thanks in advance for any advice!

[dchang0]

Might just be weak ammo that is failing to overcome the brand new recoil spring. If you're shooting Winchester White Box or some other cheapo stuff, it's typically underloaded.

[reidnez]

Might just be weak ammo that is failing to overcome the brand new recoil spring. If you're shooting Winchester White Box or some other cheapo stuff, it's typically underloaded.

Wouldn't that cause a functioning issue though? It's feeding, firing and ejecting perfectly. The slide not locking back is the only issue. In any case, you're right, it definitely isn't broken-in yet and needs a few hundred more rounds next weekend.

Forgot to mention the ammo. I was using a mix of range reloads and some Barnes +P hollowpoints.

[dchang0]

Well, the rounds might be powerful enough to eject the round but just barely underpowered to push the slide all the way back to lock.

But the +P rounds definitely wouldn't have that trouble, so yes, the mags are looking to be more culpable.

[HCz]

Some range reloads, if not all, are a bit wekaer than factory ammo. So there is a possibility that the ammo was enough to cycle the slide, but not enough to push the slide back to the point where it locks open.

My suggestion is to use factory ammo for next session, and see if that helps. If the problem still exists, you might be looking at the weakened magazine spring.

[sammy]

Pick the gun up and dry fire it. Now look at the position of your thumbs. If they are in any touching the slide stop that is your problem. Chances are you have large hands and durring recoil you bump the stop. Try loading one round in the mag and shoot the gun one handed. Repeat 10 times and I am 99% sure it will lock back every time. Sammy

[reidnez]

Thanks all three of you!

@Sammy: Yeah, that is my suspicion barring a bad magazine--which I'm doubting more, since it locks back by hand ever single time. I was military-trained (on a Beretta) to use a "high, firm grip" so there's a good chance my thumb is tripping the lever. I'd love to blame it on the pistol but it sounds like operator error.

[Rob Roy]

Pick the gun up and dry fire it. Now look at the position of your thumbs. If they are in any touching the slide stop that is your problem. Chances are you have large hands and durring recoil you bump the stop. Try loading one round in the mag and shoot the gun one handed. Repeat 10 times and I am 99% sure it will lock back every time. Sammy

+1 on that. The most likely cause.